Intermittent fasting (IF) alternates periods of eating with long periods of not eating (fasting). If you’re considering incorporating fasting into your lifestyle, here are some answers to some frequently asked questions.

How long should I fast for?

It depends. Some methods recommend 14–16 hours, some recommend 24-hour periods. True “fasting” doesn’t begin until about 10–12 hours after a meal, so you can start with 12 hours and gradually build up to longer periods of time.

Won’t I get hungry?

Again, that depends. Many people aren’t normally hungry in the morning. If you can extend the amount of time after waking up until your first meal, it can actually be quite easy to go 14–16 hours without eating.

Can I drink anything during the fast?

You can drink water, tea, and black coffee. Some plans also allow clear bone broth during the fasting periods.

Can I exercise while I’m fasting?

Exercising while fasting actually allows you to burn more fat during your workout. While going for a long walk or a short jog, doing some easy-to-moderate cardio, or taking a yoga class are all encouraged while fasting, more strenuous exercise may be too much for the body to handle in the fasted state. Use your own judgment. If you find yourself getting too hungry or lightheaded, you should cut back on the exercise on fasting days.

How often should I fast?

It depends on the method, but you can fast as little or as often as you’d like. Even skipping a couple of meals here and there has benefits. A 24-hour fast once a month or once a week is the next step up from that. Incorporating periods of fasting into your day every day is a very popular method. And many people fast every other day.

Is there anyone who shouldn’t fast?

In general, people with Type 1 diabetes (who require insulin), pregnant or nursing women, and those with certain other illnesses shouldn’t fast. To be sure, check with your health care professional to make sure it is safe for you to fast.